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September 17, 2008

Recent Dinosaur Fossil Discoveries New To Science

by Sam Savage

A new British assessment has found that most of the recently discovered dinosaurs are indeed new to science.

With many past fossil finds named on the basis of partial remains, there has been concern that a significant amount double counting has been taking place. Indeed, recent studies had even suggested this error rate might be as high as 50%, with some species being cataloged with several aliases.

However, the new assessment finds that modern practice is now very good.

Benton reviewed the original descriptions of all 1,047 species of dinosaurs ever named, from 1824 until now. He then assessed the quality of the specimens on which the names were founded, the type specimens, and found that some 500 were genuinely distinct. The certainty surrounding the latest discoveries, about two new species a month, was now very high.

"The bane of the dinosaurologist's life is species that have been named on the basis of incomplete specimens," Professor Benton said.

"In Victorian times, paleontologists were keen to name new species, and in the excitement of the great 'bone wars' for example, from 1870 to 1890, they rushed into print with new names for every odd leg bone, tooth, or skull cap that came their way.

"Later work, on more complete specimens, reduced more than 1,000 named dinosaurs to 500 or so."

Since 1960, the large majority of new species were founded on complete specimens, sometimes even entire skeletons.

As a student of dinosaur evolution, Professor Benton has a critical interest in the subject, and is trying to understand how this iconic animal group adapted and diversified over almost 200 million years.

"There's no point somebody such as myself doing big statistical analyses of numbers of dinosaur species through time - or indeed any other fossil group - if you can't be confident that they really are genuinely different," he said.

"This is important also for studies of modern biodiversity. People have also been looking at our current knowledge of mammals and insects and other animal groups and asking the simple question: are the species totals and lists we use for important conclusions - including to give political advice about endangered species - are they correct?"

"There's been a big debate about vast extinctions among amphibians. We have to know what the species are first, before we can talk about that."

Professor Benton's report was published in the journal Biology Letters.